Dissertation

Big simulations for big problems

In this thesis we investigate cosmology and the large scale structure of the Universe using cosmological simulations.

Author: R.H. Kugel
Date: 16 January 2025
Links: Thesis in Leiden Repository

The fields of cosmology, numerical cosmology, structure formation and galaxy clusters are introduced. Then we discus a machine learning method to set up subgrid models in numerical simulations, which we use to set up the FLAMINGO simulation suite. With this method we can calibrate our models directly to the observational data, without the needed of running thousands of hydrodynamical simulations. We then investigate selection effects on galaxy clusters and their impact on cosmology. Finding that for upcoming surveys the careful modeling of your selection effects is very important, and current models do not have the degree of accuracy required to make clear statements about the inferred cosmology. In the final chapter we investigate the large scale flows of the universe, and their origin. We find that the mass contained in filaments is the main driver of cosmic dynamics. However for the smaller scale structures, voids also provide an important contribution.